We are requesting funding for the purchase of a Laser Scanning Confocal Microscope under the Shared Instrumentation Grant Program. The proposed instrument is a BioRad R2000/KR-3 confocal system equipped with a Nikon Eclipse TE300 microscope. Acquisition of this instrument by the sponsoring institution is required to carry out the following studies: 1) investigating the role of p38 MAP kinase signaling complexes as mediators of the cardiac stress response; 2) establishing the structural domains of Emt/Itk that are required for T cell activation; 3) regulation of intracellular calcium and the morphology of cardiac myocytes by MAP kinases; 4) contractile protein isoform function; 5) determination of peroxisomal targeting signals; and 6) structure and functional analyses of mitochondria by electron tomography. The confocal microscope will be housed in the Electron Microscope Facility in the Department of Biology at SDSU. The facility presently houses scanning and transmission electron microscopes, a freeze fracture machine, a Nikon epifluorescence microscope and other related instruments. Daily administration, technical supervision, and training for the proposed instrument will be the responsibility of the full-time director of the Facility, Dr. Steven B. Barlow. An advisory committee, composed of the EM Facility Director and two of the participants on this proposal (Glembotski and Tsoukas), will supervise instrument operation and maintenance. This committee will meet regularly to discuss issues pertaining to operation of the proposed instrument. Use of the confocal microscope will be by appointment, scheduled in advance, on a first-come first-served basis. A user fee will be established by the advisory committee in collaboration with the other participants on this proposal and the Chair of Biology. We estimate that this fee will be approximately $20-30 per hour. Since the salary of the facility director is already covered by the department, the user fees collected will be placed in a fund to be used exclusively for instrument maintenance and repair. It is anticipated that user fees will be sufficient to cover most of the instrument-related maintenance needs. As indicated in the attached letter from the Chair of Biology, any additional required funds will be provided by the department.